肺炎支原体（Mp）和其感染的宿主细胞均可合成活性氧，但目前在Mp仅报道硫氧还蛋白系统可降解活性氧。课题组发现Mp渗透压诱导蛋白C（OsmC）超家族成员MPN625和MPN668可降解过氧化氢和有机氢过氧化物。本项目在前期研究基础上，提出“OsmC超家族蛋白MPN625和MPN668可保护Mp抵抗氧化损伤，铁吸收调节蛋白（Fur）在转录水平调控其基因表达，两种蛋白发生磷酸化修饰调节其抗氧化作用”这一科学假说。项目拟明确MPN625和MPN668的抗氧化活性与其在Mp的定位；研究Fur调节mpn625和mpn668基因表达的分子机制；鉴定MPN625和MPN668蛋白的磷酸化位点；探究磷酸化对两种蛋白抗氧化活性的影响；筛选并鉴定催化两种蛋白磷酸化的蛋白激酶。研究结果将丰富Mp的抗氧化系统，阐明Mp感受氧化压力的应答机制，有望发现Mp新的蛋白激酶，并可能为研制抗Mp药物提供新靶标。

Mycoplasma pneumoniae (M.pneumoniae) and its infected host cells can synthesize reactive oxygen species. However, only the thioredoxin system has been reported to degradate oxygen species and protect M.pneumoniae against oxidative damage. Our research team found that MPN625 and MPN668 proteins, the only two members of osmotically inducible protein C superfamily proteins of M.pneumoniae, could degrade hydrogen peroxide and organic hydroperoxides. Based on the previous research, we proposed that OsmC superfamily proteins MPN625 and MPN668 are antioxidant proteins of M.pneumoniae, iron uptake regulatory protein (Fur) can regulate MPN625 and MPN668 genes expression at the transcriptional level, subsequently, two proteins undergo phosphorylation modification to regulate their antioxidant activities. . This project intends to furter clarify the antioxidant activities of two proteins using gene knockout and complementation techniques; Study the regulation and molecular mechanism of Fur on the expression of MPN625 and MPN668 genes under hyperoxia by promoter analysis, EMSA, and DnaseⅠfootprint; Analysis of phosphorylation of MPN625 and MPN668 and identification of their phosphorylation sites by Phos-tag™ Acrylamide and LC-MS/MS. By now, HPrK and PrkC are the only two protein kinases in M.pneumoniae, but they account for only five protein phosphorylation events, which is not including the identifed phosphorylated MPN625 protein. So our project will explore whether MPN625 and MPN668 are capable of autophosphorylating or phosphorylated by a new protein kinase. If the answer is the latter, we will screen and identify protein kinases that catalyze the phosphorylation of two proteins using gel permeation chromatography or Affinity Enhancement-Mass Spectrometry.The results of this study will enrich the antioxidant system of M.pneumoniae, elucidate the response mechanism of M.pneumoniae sensing oxidative stress and hope to discover new protein kinases of M.pneumoniae, and may provide new targets for the development of anti-M.pneumoniae drugs.